The federal government filed a lawsuit today against the energy company for violations of the Clean Air Act.
The suit alleges that Ameren made multi-million-dollar modifications to its coal-fired power plant in Festus (map image above), without installing required pollution controls and obtaining the necessary permits.
The government wants Ameren to reduce sulfur dioxide emissions, to address any harm caused by the violations, and to pay civil penalties.
Ameren spokesperson Susan Gallagher says the company did nothing wrong.
"We believe that the position that the EPA is taking will impose significant costs on Ameren customers, especially in tough economic times."
Gallagher says the modifications at the Festus plant consisted of routine maintenance projects allowed under the Clean Air Act.